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Diffstat (limited to 'sound/soc/codecs/rt5677-spi.c')
| -rw-r--r-- | sound/soc/codecs/rt5677-spi.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/sound/soc/codecs/rt5677-spi.c b/sound/soc/codecs/rt5677-spi.c new file mode 100644 index 000000000..06abcd017 --- /dev/null +++ b/sound/soc/codecs/rt5677-spi.c @@ -0,0 +1,237 @@ +/* + * rt5677-spi.c -- RT5677 ALSA SoC audio codec driver + * + * Copyright 2013 Realtek Semiconductor Corp. + * Author: Oder Chiou <oder_chiou@realtek.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/module.h> +#include <linux/input.h> +#include <linux/spi/spi.h> +#include <linux/device.h> +#include <linux/init.h> +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/slab.h> +#include <linux/gpio.h> +#include <linux/sched.h> +#include <linux/uaccess.h> +#include <linux/regulator/consumer.h> +#include <linux/pm_qos.h> +#include <linux/sysfs.h> +#include <linux/clk.h> +#include <linux/firmware.h> + +#include "rt5677-spi.h" + +#define RT5677_SPI_BURST_LEN 240 +#define RT5677_SPI_HEADER 5 +#define RT5677_SPI_FREQ 6000000 + +/* The AddressPhase and DataPhase of SPI commands are MSB first on the wire. + * DataPhase word size of 16-bit commands is 2 bytes. + * DataPhase word size of 32-bit commands is 4 bytes. + * DataPhase word size of burst commands is 8 bytes. + * The DSP CPU is little-endian. + */ +#define RT5677_SPI_WRITE_BURST 0x5 +#define RT5677_SPI_READ_BURST 0x4 +#define RT5677_SPI_WRITE_32 0x3 +#define RT5677_SPI_READ_32 0x2 +#define RT5677_SPI_WRITE_16 0x1 +#define RT5677_SPI_READ_16 0x0 + +static struct spi_device *g_spi; +static DEFINE_MUTEX(spi_mutex); + +/* Select a suitable transfer command for the next transfer to ensure + * the transfer address is always naturally aligned while minimizing + * the total number of transfers required. + * + * 3 transfer commands are available: + * RT5677_SPI_READ/WRITE_16: Transfer 2 bytes + * RT5677_SPI_READ/WRITE_32: Transfer 4 bytes + * RT5677_SPI_READ/WRITE_BURST: Transfer any multiples of 8 bytes + * + * Note: + * 16 Bit writes and reads are restricted to the address range + * 0x18020000 ~ 0x18021000 + * + * For example, reading 256 bytes at 0x60030004 uses the following commands: + * 0x60030004 RT5677_SPI_READ_32 4 bytes + * 0x60030008 RT5677_SPI_READ_BURST 240 bytes + * 0x600300F8 RT5677_SPI_READ_BURST 8 bytes + * 0x60030100 RT5677_SPI_READ_32 4 bytes + * + * Input: + * @read: true for read commands; false for write commands + * @align: alignment of the next transfer address + * @remain: number of bytes remaining to transfer + * + * Output: + * @len: number of bytes to transfer with the selected command + * Returns the selected command + */ +static u8 rt5677_spi_select_cmd(bool read, u32 align, u32 remain, u32 *len) +{ + u8 cmd; + + if (align == 4 || remain <= 4) { + cmd = RT5677_SPI_READ_32; + *len = 4; + } else { + cmd = RT5677_SPI_READ_BURST; + *len = (((remain - 1) >> 3) + 1) << 3; + *len = min_t(u32, *len, RT5677_SPI_BURST_LEN); + } + return read ? cmd : cmd + 1; +} + +/* Copy dstlen bytes from src to dst, while reversing byte order for each word. + * If srclen < dstlen, zeros are padded. + */ +static void rt5677_spi_reverse(u8 *dst, u32 dstlen, const u8 *src, u32 srclen) +{ + u32 w, i, si; + u32 word_size = min_t(u32, dstlen, 8); + + for (w = 0; w < dstlen; w += word_size) { + for (i = 0; i < word_size; i++) { + si = w + word_size - i - 1; + dst[w + i] = si < srclen ? src[si] : 0; + } + } +} + +/* Read DSP address space using SPI. addr and len have to be 4-byte aligned. */ +int rt5677_spi_read(u32 addr, void *rxbuf, size_t len) +{ + u32 offset; + int status = 0; + struct spi_transfer t[2]; + struct spi_message m; + /* +4 bytes is for the DummyPhase following the AddressPhase */ + u8 header[RT5677_SPI_HEADER + 4]; + u8 body[RT5677_SPI_BURST_LEN]; + u8 spi_cmd; + u8 *cb = rxbuf; + + if (!g_spi) + return -ENODEV; + + if ((addr & 3) || (len & 3)) { + dev_err(&g_spi->dev, "Bad read align 0x%x(%zu)\n", addr, len); + return -EACCES; + } + + memset(t, 0, sizeof(t)); + t[0].tx_buf = header; + t[0].len = sizeof(header); + t[0].speed_hz = RT5677_SPI_FREQ; + t[1].rx_buf = body; + t[1].speed_hz = RT5677_SPI_FREQ; + spi_message_init_with_transfers(&m, t, ARRAY_SIZE(t)); + + for (offset = 0; offset < len; offset += t[1].len) { + spi_cmd = rt5677_spi_select_cmd(true, (addr + offset) & 7, + len - offset, &t[1].len); + + /* Construct SPI message header */ + header[0] = spi_cmd; + header[1] = ((addr + offset) & 0xff000000) >> 24; + header[2] = ((addr + offset) & 0x00ff0000) >> 16; + header[3] = ((addr + offset) & 0x0000ff00) >> 8; + header[4] = ((addr + offset) & 0x000000ff) >> 0; + + mutex_lock(&spi_mutex); + status |= spi_sync(g_spi, &m); + mutex_unlock(&spi_mutex); + + /* Copy data back to caller buffer */ + rt5677_spi_reverse(cb + offset, t[1].len, body, t[1].len); + } + return status; +} +EXPORT_SYMBOL_GPL(rt5677_spi_read); + +/* Write DSP address space using SPI. addr has to be 4-byte aligned. + * If len is not 4-byte aligned, then extra zeros are written at the end + * as padding. + */ +int rt5677_spi_write(u32 addr, const void *txbuf, size_t len) +{ + u32 offset; + int status = 0; + struct spi_transfer t; + struct spi_message m; + /* +1 byte is for the DummyPhase following the DataPhase */ + u8 buf[RT5677_SPI_HEADER + RT5677_SPI_BURST_LEN + 1]; + u8 *body = buf + RT5677_SPI_HEADER; + u8 spi_cmd; + const u8 *cb = txbuf; + + if (!g_spi) + return -ENODEV; + + if (addr & 3) { + dev_err(&g_spi->dev, "Bad write align 0x%x(%zu)\n", addr, len); + return -EACCES; + } + + memset(&t, 0, sizeof(t)); + t.tx_buf = buf; + t.speed_hz = RT5677_SPI_FREQ; + spi_message_init_with_transfers(&m, &t, 1); + + for (offset = 0; offset < len;) { + spi_cmd = rt5677_spi_select_cmd(false, (addr + offset) & 7, + len - offset, &t.len); + + /* Construct SPI message header */ + buf[0] = spi_cmd; + buf[1] = ((addr + offset) & 0xff000000) >> 24; + buf[2] = ((addr + offset) & 0x00ff0000) >> 16; + buf[3] = ((addr + offset) & 0x0000ff00) >> 8; + buf[4] = ((addr + offset) & 0x000000ff) >> 0; + + /* Fetch data from caller buffer */ + rt5677_spi_reverse(body, t.len, cb + offset, len - offset); + offset += t.len; + t.len += RT5677_SPI_HEADER + 1; + + mutex_lock(&spi_mutex); + status |= spi_sync(g_spi, &m); + mutex_unlock(&spi_mutex); + } + return status; +} +EXPORT_SYMBOL_GPL(rt5677_spi_write); + +int rt5677_spi_write_firmware(u32 addr, const struct firmware *fw) +{ + return rt5677_spi_write(addr, fw->data, fw->size); +} +EXPORT_SYMBOL_GPL(rt5677_spi_write_firmware); + +static int rt5677_spi_probe(struct spi_device *spi) +{ + g_spi = spi; + return 0; +} + +static struct spi_driver rt5677_spi_driver = { + .driver = { + .name = "rt5677", + }, + .probe = rt5677_spi_probe, +}; +module_spi_driver(rt5677_spi_driver); + +MODULE_DESCRIPTION("ASoC RT5677 SPI driver"); +MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>"); +MODULE_LICENSE("GPL v2"); |